The British Comet tank, mounted the new 77 mm HV gun in a new lower profile and part-cast turret. This gun was effective against late war German tanks, including the Panther and, at most ranges, the Tiger.

The tank was widely respected as one of the best British tanks of the war, and continued in service afterward.The Comet had a maximum speed of 32 miles per hour (51 km/h) was greatly exploited on the German Autobahn.

Hi George--how are things with you ??? Because the Comet made the Challengertank obsolete-thus development of the Centurion commenced c.1944

With the A34 (the General Staff specification), later named Comet, the tank designers opted to correct some of the Cromwell's flaws in armament, track design and suspension while building upon the Cromwell's main strengths, its low height, high speed and mobility. This replaced the need for Challenger and Firefly, and acted upon the experiences gained through design and early deployment of Cromwell.

George is correct, the Meteor engine was a challenge. A Cummins diesel was a satisfactory solution.

Yes, Jim, not sure you could call it a topgap - with the war over, it lingered until 1958, so a 14 year "stopgap", their service overlapped with the Centurion. One reason was budget (the Centurion was a VERY expensive tank).

It missed the Korean war but manned up with the BAOR. I can remember the Irish Army still using them in the 1970s in the Glen of Imaal training ground. The only reason they retired them was the lack of 77mm ammo, the running gear and mechanics were still running well. They were almost 30 years old!

OK SJ-what you have stated poses a question -just how good was the Comet and why was it superseded by the Centurion an expensive AFV.???

Regards

Jim--anemone

Jim

It comes down to the Holy Trinity of tank design - Armour - Armament - Mobility.. British tankers were traumatised in WW2 with being both outgunned and too light in armour. This swung British tank design towards the Centurion over the lighter mobile Comet. The Germans went with mobility in Leopard I, but reverted to Armour & Armament in Leopard II, taking on board the lessons learnt in the Middle East by the IDF which vindicated the Cent design.

1.Compare the design slope of the armour. Comet is a box with lots of "shot trap", Cent is sloped at angles. The slope deflects AT rounds and reduces penetration as angled armour is thicker in cross section

2. The thickness of the armour- The Cent has up to 152mm, Comet is 102mm with only 14mm on front belly

3. The gun. Comet has the 77mm (sic) - really a cut down 75mm (17 pounder) with reduced muzzle velocity and penetration. The Cent started off with the 20pounder and ungraded to the legendry L5 105mm-

4. I read the combat reports of a New Zealand Tanker who was attached to the Royal Irish Hussars in Korea. The Centurion crews invented a new tanker term "swanning" - a tribute to how the Cent could swan around the killing ground.

5 15 nations purchased the Centurion. A late production 1960's Cent was £50k ! It was simply the "Best in the West". Period. In Vietnam the Aussie Cents were much feared by the VC/NVA because of their thick armour and beehive Anti Personnel rounds.

The Comet was a good tank for 1944, sadly it perpetuated the design defects of the Cromwell, however to remove them would have involved extensive redesign and new jigs for the Layland factory. This was not possible in 1943.

By contrast the Centurion was a "blue sky" drawing board design in answer to all the wartime demands/prayers of the British tankers. The only flaw was slow speed/range, but upgrades during its decades of service solved these niggles. In an earlier post I stated that the IDF fitted a Cummins - it may have been an Allison ?

It was also capable of so much upgrade and modification. Not just AFV mode, but versions for the Royal Engineers and Royal Artillery. The AVRE soldiered into the 1980s as did gunner's OPRA with its Christmas Tree. And when I stepped shore on the Falkland Islands, the first tracked vehicle I saw was a Centurion BARV.

The Israelis have modified their Centurions into APCs and engineer vehicles. One young IDF tanker checked the serial number on his Centurion chassis, and it was the very vehicle his father had soldiered in back in 1970s!

I must profess to an almost complete lack of familiarity with WW2 British tanks, but the Comet reminds me in some ways of the U.S. M24 Chaffee light tank. I can't help wondering if some of the same factors entered into its design.

---------------Jim Cameron

Every time I go to Gettysburg, I learn two things. Something new, and, how much I still don't know.

I must profess to an almost complete lack of familiarity with WW2 British tanks, but the Comet reminds me in some ways of the U.S. M24 Chaffee light tank. I can't help wondering if some of the same factors entered into its design.--Jim Cameron

To a point Jim. The M24 was a "light tank". The Brits stopped doing light tanks (apart from Tretrarch)early in WW2 and doctrine emphasised two categories. The infantry tank which would support infantry (Churchill is a classic example) and the Cruiser type tank that would be fast and scout, based in the Christie suspension. Yet the Cruiser concept was an oxymoron as it was expected to fight it out with German "MTBs" like the PzKpfw III & IV.

The Cromwell was the epitome of the Cruiser design but its design was protracted and it missed North Africa where it would have shone on terms at an adequate 6pdr gun, reasonable armour and superior mobility. By the time it came available, it was outclassed. The Comet is a budget attempt to use a lot of Cromwell components to make a better tank.

Both Cromwell(61,000lbs)and Comet(78,800lbs) would have been heavier than a Chaffee (40,500 lbs), so neither can be classed as "light".

I suppose that part of the problem is that the U.S. light and medium categories don't necessarily equate to the British "Infantry" and "cruiser" designations. And even the U.S. M5/M5A1 was large compared to most European light tanks, and in many respects like a cruiser. The M24, for its part, was also mainly a scout, with light armor in the Tank Destroyer range, not really meant to slug it out with enemy tanks.Did the designs of both the Comet and the M24 in some respects reflect a lessened German armored threat toward the end of the war? Or, and effort on the part of both countries to produce a more survivable and better armed light tank/cruiser?

---------------Jim Cameron

Every time I go to Gettysburg, I learn two things. Something new, and, how much I still don't know.

I suppose that part of the problem is that the U.S. light and medium categories don't necessarily equate to the British "Infantry" and "cruiser" designations. And even the U.S. M5/M5A1 was large compared to most European light tanks, and in many respects like a cruiser. The M24, for its part, was also mainly a scout, with light armor in the Tank Destroyer range, not really meant to slug it out with enemy tanks.Did the designs of both the Comet and the M24 in some respects reflect a lessened German armored threat toward the end of the war? Or, and effort on the part of both countries to produce a more survivable and better armed light tank/cruiser?--Jim Cameron

I wouldn't have thought so Jim. First, the M3/M5 "Stuart" was kept in production way past its shelf life as it allowed American industry to make its tank quota. The puny 37mm was long obsolete. Only a failure to mount a bigger gun in the M5 eventually stimulated a new design from Cadillac that was to emerge as Light Tank M24

The M24 cannot be defined as a tank destroyer - its 75mm low velocity gun did not cut it. But it was cheap and so much better than the M5. However most American tank formations would have preferred another squadron of M4A3 Shermans.

What we can say is that the appearance of the Panther & Tiger did at last pressure the US military to think beyond the Sherman (so good for mass production) and invest development in the M26 which is the design basis for several generations of US tanks up to the M60.

I wasn't saying the M24 was a tank destroyer. Only that it had similarly light armor.As far as the M3/M5 series, my impression is that obsolete or not, there were so many of them that the U.S. had no real choice but to find a role for them.

---------------Jim Cameron

Every time I go to Gettysburg, I learn two things. Something new, and, how much I still don't know.

I wouldn't have thought so Jim. First, the M3/M5 "Stuart" was kept in production way past its shelf life as it allowed American industry to make its tank quota. The puny 37mm was long obsolete. Only a failure to mount a bigger gun in the M5 eventually stimulated a new design from Cadillac that was to emerge as Light Tank M24

Not exactly. The M3/M5 series of light tanks continued in production to meet the requirement for tanks of that type by the US Army and for Lend-Lease. The "tank quotas" given to the War Department and by them to industry were set by FDR as light, medium, and heavy tanks by year and were benchmarks more than anything.

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The M24 cannot be defined as a tank destroyer - its 75mm low velocity gun did not cut it. But it was cheap and so much better than the M5. However most American tank formations would have preferred another squadron of M4A3 Shermans.

The M24 was intended as the light tank incorporating all the lessons learned from the M3/M5 and pretty much was exactly that. It was by far the best light tank of the war. It is also interesting that opinion on the utility of the light tank company in the battalion in the ETO was mixed. Some wanted it replaced by another 75mm/76mm medium company, some with a 105mm medium company, some wanted to retain it.

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What we can say is that the appearance of the Panther & Tiger did at last pressure the US military to think beyond the Sherman (so good for mass production) and invest development in the M26 which is the design basis for several generations of US tanks up to the M60.

The M26 was not a reaction to the Panther...it was authorized for development 24 May 1943, long before the Panther entered combat at Kursk and much longer before the Western Allies had any real knowledge of it. Nor was there any reaction to the Tiger, since it was never seen as a threat, given the assessment of its possible numbers and capabilities.

Interesting but orthodox interpretation. Can you quote your primary/secondary source evidence for these arguments ? And I mean something beyond Wikipedia.

Whilst we wait the dawn of the new day to reach America, a little synopsis of where this thread could run.

Its old ground for me, a much favoured tutorial topic by the late Col George Forty(the father of Bovington).

Two competing interpretations exist, and the largely revolve around the career and influence of General McNair. Much was done to protect his reputation after WW2, and he still has his devotees such as Mark T Cahoun who would advance the orthodox argument that the US army had the right tanks at the right time.

The revision (and I am of that school) is characterised by Steve Zaloga, arguing that McNair had a WW1 mindset and thwarted visionaries such as General Jacob Devers.

A good balanced introduction via the historiography - to the debate which this thread may well engage in - is Robert S Cameron, "Mobility, shock and firepower: the emergence of the US Army Armour Branch" (Centre for Military History, Washington,2009/15)

Whilst we wait the dawn of the new day to reach America, a little synopsis of where this thread could run.

Its old ground for me, a much favoured tutorial topic by the late Col George Forty(the father of Bovington).

Two competing interpretations exist, and the largely revolve around the career and influence of General McNair. Much was done to protect his reputation after WW2, and he still has his devotees such as Mark T Cahoun who would advance the orthodox argument that the US army had the right tanks at the right time.

The revision (and I am of that school) is characterised by Steve Zaloga, arguing that McNair had a WW1 mindset and thwarted visionaries such as General Jacob Devers.

A good balanced introduction via the historiography - to the debate which this thread may well engage in - is Robert S Cameron, "Mobility, shock and firepower: the emergence of the US Army Armour Branch" (Centre for Military History, Washington,2009/15)

So fasten your seat belts and we will await Richto90's reply... --SJ

Or, since it is dawn here, now, we could look at:

Baily, Charles M. The Development of American Tank Destroyers during World War II: The Impact of Doctrine, Combat Experience, and Technology on Material Acquisition. Fort Leavenworth, KS, 1976._____. Faint Praise: American Tanks and Tank Destroyers during World War II. Hamden, Conn: Archon Books, 1983.

BTW, since Baily's balanced interpretation is now little known, since he died too early, Zaloga's has dominated the historiography since the 1980's, so is in fact the "orthodox interpretation", rather than a "revision". However, much of that is based on the simple fact that the original historiographic interpretation was by the Ordnance department postwar, when McNair had little or no means of replying.

Also BTW, who is "Cahoun"? Meanwhile, Cameron, while presenting an excellent doctrinal and organizational history, touches lightly on the technical, developmental, and industrial mobilization issues confronting the U.S.

So do you want to drag poor old Belton into it too or are your seatbelts too tight for that?

Thank you for that. hmmm lots of manuals. The craft of good history lies however in interpretation. Have you published ?

Anyway, Its a wet afternoon, lets open the debate. The M26 is a good starting point.

I would respectfully suggest you look at the correspondence Devers to Marshall (16 Dec 1943). The M26, far from being approved - "authorised for development" [sic] as you have argued, was in grave danger of never getting produced for WW2 service at all!!!!

It was only the intervention by Marshall that saved it. The naïve argument by the McNair camp was that (a) tank killers on an M4 chassis could do the job,and(b)that the M26 was unfit for combat -to quote the manuals - as the size of US tanks was limited to the capacity of the Corps of Engineers bridges.

It was pointed out by those on the sharp end that (a) the German Army had not read the Corp of Engineers manual on the capacity of bridges and (b) were not constrained by such limitations.

Agree as to Zaloga having become, by sheer volume of publication if nothing else, the prevailing "orthodox interpretation."

My layman's understanding is that McNair, by training and experience an artilleryman, tended to see AT defense as primarily a job for towed AT guns. His preference for towed TD battalions is generally portrayed as wrongheaded and a serious mistake, substituting a clearly inappropriate structure for the already questionable SP battalions. Much of this debate is further complicated by the fact the U.S. towed 3" AT gun was both heavier and less effective than its peers, and disagreement over the proper design (M18 v. M10) for the SP TD.

---------------Jim Cameron

Every time I go to Gettysburg, I learn two things. Something new, and, how much I still don't know.

Actually, not many manuals in that list. Among other items, a lot of material like after-action reports.

Cheers

BW--BWilson

I stopped counting at seven, and to be honest, I never give marks for a cut and paste bibliography or reading list. Its the academic ability to use a reference footnote to buttress an argument that makes good history.

Rich,I recently came across a photo of one of my uncles who was in the 601st TD BN, on his return from overseas, wearing a 3rd Infantry Division patch.The TD battalions had their own insignia, and weren't organic to the division they were attached to. Was this sort of thing common, or was this more a reflection of the long association between these two units?

---------------Jim Cameron

Every time I go to Gettysburg, I learn two things. Something new, and, how much I still don't know.

Rich,I recently came across a photo of one of my uncles who was in the 601st TD BN, on his return from overseas, wearing a 3rd Infantry Division patch.The TD battalions had their own insignia, and weren't organic to the division they were attached to. Was this sort of thing common, or was this more a reflection of the long association between these two units?--Jim Cameron

Jim, most of the separate battalions were granted Distinctive Unit Insignia, many of them fairly generic. USAMHI has a complete collection and will usually send you a black and white for a particular battalion.

It was not unusual at all for separate battalions to identify with divisions they were regularly attached to. For my dad's 537th AAA AW Bn (mbl) it was the 90th ID. The 712th Tank Battalion had the same affinity. The problem with the separate battalions was typical for the US Army...efficiency was the rational, but the battalions, unless regularly affiliated with a parent group HQ - rare except for some AAA, FA, and Engineers - often became orphans.

Thank you for that. hmmm lots of manuals. The craft of good history lies however in interpretation. Have you published ?

Anyway, Its a wet afternoon, lets open the debate. The M26 is a good starting point.

And I'm in a hotel on the Oregon Coast, returning from vacation, so sure, the M26 is a good starting point.

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I would respectfully suggest you look at the correspondence Devers to Marshall (16 Dec 1943). The M26, far from being approved - "authorised for development" [sic] as you have argued, was in grave danger of never getting produced for WW2 service at all!!!!

...um, Jake Devers did not correspond to Marshall on 16 December...Army G-4, Major General Russell Maxwell did, in response to Devers cable of 13 November 1943. Devers, formerly commanding general of the Armored Force, now commanding general of the European Theater of Operations, sent a request for production of 250 T26 tanks for units in the ETO. That was after Gladeon Barnes jumped the gun (for about the umpteenth time) on 13 September 1943 and requested Army Service Forces authorization to produce 500 Medium Tanks T26, over and above the ten authorized in May, before completion of a single pilot. General McNair quickly non-concurred on the sensible grounds that Ordnance was buying a pig in a poke, procuring a new type before completing or testing a single pilot. After the failures of the T20, T22, and T23 designs, Army Service Forces also agreed and blocked the request.

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It was only the intervention by Marshall that saved it.

Utter and complete nonsense. The ten pilot Medium Tanks T26 and forty pilots of the Medium Tanks T25 were approved on 24 May 1943. They were in development when Devers cabled under the erroneous understanding that it was approved for production, when it actually did not exist yet. McNair simply prevented another Light/Medium Tank T7 fiasco from occurring.

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The naïve argument by the McNair camp was that (a) tank killers on an M4 chassis could do the job,and(b)that the M26 was unfit for combat -to quote the manuals - as the size of US tanks was limited to the capacity of the Corps of Engineers bridges.

No such argument was ever made, nor was there a "McNair camp" that I am aware of, although there is a Fort McNair...they have a very good library there BTW, you might benefit by visiting it. There was no argument "(b)that the M26 was unfit for combat", since it did not exist then even in pilot form and had not been tested in any way, shape, or form, so no such assessment was possible. Of course, after the pilot T26E1 was completed in january 1944 it was tested and found wanting, which is why the production design was the T26E3.

Meanwhile, the Engineers argument was not McNair's, it was the Engineers and based upon AR 850-15...do try to keep up.

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It was pointed out by those on the sharp end that (a) the German Army had not read the Corp of Engineers manual on the capacity of bridges and (b) were not constrained by such limitations.

I kind of figured where this was gonna go. Willy waggling. Okay, my publications are:

Artillery HellHitler's Last GambleCracking Hitler's Atlantic WallA dozen or so articles in the TNDM Journal.Uncounted reports for the US government.

And about nine years of research and writing on For Purpose of Service Test.

Cheers!--Richto90

Ahh. The Richard C Anderson ! Fuck me. Yes forum friends, SJ led with his chin on this one!

I defer to your research, you have indeed dug deep in the primary sources, whilst a humble vet like me was satisfied to reach to the bookshelf or listen to the lectures were WW2 US Armour is concerned. Outside my own service experience, my academic research took me deep into 18th century Ireland as a PhD and academic publication demand, and we all get lazy outside our specialist zones.

But I appreciate good history that challenges the myths and misplaced orthodoxy, and that's what you and the Dupuy school have crafted.

Yes, Foss,Weeks,Forty and Zaloga were the received view at Camberley. You have caused me to reappraise McNair- I will keep an eye for reference next time I am browsing at Kew.

[Ahh. The Richard C Anderson ! Fuck me. Yes forum friends, SJ led with his chin on this one!

Maybe I need to change my log in?

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I defer to your research, you have indeed dug deep in the primary sources, whilst a humble vet like me was satisfied to reach to the bookshelf or listen to the lectures were WW2 US Armour is concerned. Outside my own service experience, my academic research took me deep into 18th century Ireland as a PhD and academic publication demand, and we all get lazy outside our specialist zones.

NOW you're relying on an appeal to authority?

Seriously, it is a great subject of argument and I used to be of the anti McNair camp, but the more I have dug the more I have come to see the flaws in the argument. Gladeon Barnes, John Christmas, and the other principal's at Ordnance got to write the history because they lived postwar, McNair didn't. Barnes obviously saw the way things might go after Hanson Baldwin published his three-part New York Times tank scandal article in January 1945, and quickly started writing his apologia on both tank design and gun design. In them Barnes was incredibly self-serving - every error/problem was due to interference by McNair or unnamed minions at Fort Knox. They were then used without question by the authors of the three Ordnance Department histories published postwar by CMH and so on. Remember, he who writes the history gets to define what the history was...viz. the "Lost Cause" authors after the American Civil War. The old adage that the "victors write the history" is actually wrong. It should be the "survivors with a grudge write the history".

The same has happened with regards to McNair and the Tank Destroyer story. His direct involvement was early on, when he was a subject matter expert. His only other direct input was then later, after the Tunisian Campaign, when he raised the issue of towed guns. All other TD problems were created by the TD creators, principally Bruce.

No appeal to authority don't recognise it, just to the Gods. Nobody likes to be a Fig 11 , but as we say in the Gaelic we take a beating- Tiocfaidh ar la !

I fought for my tribe, researched for a living and read/blog for fun. Like all experts I know a great deal about very little, and general knowledge tends to be secondary reading.

If I have any mitigation being attracted to the anti-McNair camp, its that empathy Vets have from watched good men die because of budget cuts, defective equipment or obsolete kit whilst smug corporates making money and politicians get re-elected.

I have refused to shake the blood stained hand of Margaret Thatcher and told Tony Blair to fuck off. No OBE's for this Irish soldier.

There is a myth about Allied tankers cooking in inadequate Shermans and Honey tanks. Without doubt many did. Would better kit getting to the front earlier have saved lives? How much was due to bad tactical doctrine. I ask this because I spend a few days liaison duty in an NM-116 (Norwegian Chaffee)and played "shoot & scoot" in a defensive role, but if tasked to "execute battle reconnaissance" (as per WW2 US Army Training Circular), life expectancy would have been short in the killing ground.

Rich,Thanks as regards the shoulder patches. In my uncle's case I do suspect that the almost habitual attachment of the 601st to the 3ID probably had a lot to do with it. Those TD battalions which tended to be attached to different divisions, without forming long term relationships, probably tended to more generic insignia.

Anyway, as to McNair, he strikes me as yet another example of a man unfortunate enough to be presented to History mainly by his detractors. Design, development, adoption, and introduction into combat of new AFV's was massively complicated, with long lead times. Add to the mix differing perspectives of the various principals as to doctrine, organization, and equipment, and it's a wonder anything got done. And small wonder that some were less than pleased with the end product.

Question: Bruce was clearly not happy with the M10. But weren't there objections by the Armored board (forgive me if I have the name wrong) to the effect that it wasn't really combat ready, for such reasons as to unbalanced turret and lack of power traverse? And I must admit to wondering how complicated it would have been to provide a power traverse. Did the TD command see a power traverse as unnecessary, given how it would normally be employed?

---------------Jim Cameron

Every time I go to Gettysburg, I learn two things. Something new, and, how much I still don't know.

No appeal to authority don't recognise it, just to the Gods. Nobody likes to be a Fig 11 , but as we say in the Gaelic we take a beating- Tiocfaidh ar la !

Sorry, no Gaelic blood that I know of in me, all German, Norwegian, and English, but I understand.

Quote:

I fought for my tribe, researched for a living and read/blog for fun. Like all experts I know a great deal about very little, and general knowledge tends to be secondary reading.

If I have any mitigation being attracted to the anti-McNair camp, its that empathy Vets have from watched good men die because of budget cuts, defective equipment or obsolete kit whilst smug corporates making money and politicians get re-elected.

I have refused to shake the blood stained hand of Margaret Thatcher and told Tony Blair to fuck off. No OBE's for this Irish soldier.

For me recently it has been the Department of the Army resurrecting the "light armored vehicle" recently for no good reason. that's a critter that just won't die.

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There is a myth about Allied tankers cooking in inadequate Shermans and Honey tanks. Without doubt many did. Would better kit getting to the front earlier have saved lives? How much was due to bad tactical doctrine. I ask this because I spend a few days liaison duty in an NM-116 (Norwegian Chaffee)and played "shoot & scoot" in a defensive role, but if tasked to "execute battle reconnaissance" (as per WW2 US Army Training Circular), life expectancy would have been short in the killing ground.

--SJ

Possibly, but how to get "better kit" to the front earlier, given the reality of the time? That is one of the themes I'm touching on. The Medium Tank M3 was a direct kludge off the Medium Tank M2A1...and it took every draftsman at Rock Island Arsenal working their arses off to complete the 186 pounds of drawings required for Chrysler to set up the tooling plans for DTA...just weeks after going through the same exercise when they agreed to build the M2A1. The lack of engineers and draftsmen familiar with tank design also meant that no work was done of the "objective" medium tank, the M4, until the work was completed on the M3. The result was while the Medium Tank M4 military characteristics were laid out on 31 August 1940 the first pilot was completed 28 February 1942. And it wasn't until then that attention could be turned to designing, building, and testing the next generation of "cutting edge" designs, which ran into the typical problems associated with cutting edge design...it took a while to get them to work. Nevertheless, four years after the M2A1, we had the T26 (although it would have better been the T25). The Germans took six years to get from Pz III/IV to Panther.

The reality of the time is a useful context. The Panther development would have taken more than six years if counterfactually the T-34 had not crashed the party! Without such an encounter, would the Germans might even have stuck with the PzIV and what was to emerge as the Tiger 1 ?

There is a school of thought that the Germans should have mass produced the Pz IV - given it maximum stretch/additional armour - and stuck with it. Made it their Sherman. The premise being that the Panther and the super heavies diverted resources.

I remain impressed with what the Aussies managed to do using the M3 drive train. The Sentinel project was overtaken by the capacity of US M4 production, but as indigenous design would have been more than adequate to counter Japanese armour in that theatre. Bovington have a nice example.

Question: Bruce was clearly not happy with the M10. But weren't there objections by the Armored board (forgive me if I have the name wrong) to the effect that it wasn't really combat ready, for such reasons as to unbalanced turret and lack of power traverse? And I must admit to wondering how complicated it would have been to provide a power traverse. Did the TD command see a power traverse as unnecessary, given how it would normally be employed?--Jim Cameron

Bruce was not happy with anything that wasn't a race car with a gun on it. Many don't realize that the Armored Car M8 actually began development as a light-armored wheeled tank destroyer.

The Tank Destroyer battalions were originally intended to be Light-Towed, Light-SP, or Heavy-SP. Most were organized with a mix of towed 37mm and 75mm guns. Bruce quickly decided the Heavy-SP battalion, armed with a 3" Gun was the way to go, but considered the M10, adapted from the Medium Tank M4A2, an interim stopgap at worst and a training vehicle at best. However, the lack of a power traverse was originally just to save space and weight, given that the initial belief was the TD would engage from ambush and at longer ranges, so would not require such. The turret balance issue was solved by weights attached to the rear of the turret and was never critical.

As for the "Armored Board", it was part of the Armored Force and had no role in the selection of Gun Motor Carriages for the Tank Destroyers. That was the Tank Destroyer Board. Each field tested vehicle pilots submitted to them to meet its requirements. Those requirements went to the Ordnance Committee, which consisted of representatives from all the combat branches and service departments. The Ordnance Committee reviewed requests, technical proposals to meet requests, and other detailed reports regarding Ordnance material development and voted on what to do with them. However, the end user got to do field testing and recommended changes and could thumbs up or thumbs down a design...sometimes arbitrarily. In the spring of 1942 for example, the Armored Force suddenly decided against diesel-powered tanks after nearly two years of agreeing to such development and after Ordnance had invested a total of seven years in radial diesel engine development. Armor also decided it didn't like gasoline radials either and wanted the newly designed Ford GA-series of engine in all its medium tanks and vehicles based on the medium tank chassis...at a time when the engine was not fully developed or tested and production had barely begun. Then they turned down the initial design of the 76mm-armed Medium Tank M4 because it wasn't perfect, leaving the Tank Destroyers to scarf up priority on the new 76mm gun. BTW, those were all Jake Devers's decisions, from the man who was widely considered to be the smartest American Army general officer in Word War II.

If the users could be arbitrary though, so could Ordnance, especially Gladeon Barnes. Like Ferdie Porsche he became enamored with a gasoline-electric drive system, which was an elegant engineering solution that was impractical for use in a tank. So enamored that he nearly derailed the T26 program by insisting that a pilot with electric drive be completed, long after the Armored Force had passed on it in the T23. It was actually the T26 with electric drive he tried to push on Devers and Marshall in November 1943, long before the conventionally engined T26E1 pilot was completed. So if his con job had succeeded the Army might have been stuck with another T23...250 limited production tanks that nobody wanted.

The reality of the time is a useful context. The Panther development would have taken more than six years if counterfactually the T-34 had not crashed the party! Without such an encounter, would the Germans might even have stuck with the PzIV and what was to emerge as the Tiger 1 ?

In theory it should have taken longer given that the Army General Staff cancelled development of 35-40 ton class tanks powered by 700hp engines on the outbreak of war. However, Porsche independently continued development of the VK30.01 (P) and Henschel the VK30.01 (H), which were intended to be the successor to the Panzer IV. Porsche of course insisted on an electric drive, which went rapidly no where. The Henschel pilots were completed in 1941, but were discarded for an all new design for the Panther proposal, while work continued on a variant, the VK36.01 (H), which led eventually to the Tiger.

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There is a school of thought that the Germans should have mass produced the Pz IV - given it maximum stretch/additional armour - and stuck with it. Made it their Sherman. The premise being that the Panther and the super heavies diverted resources.

The reason for the VK 30.01 development series was to replace the Panzer IV, which was a troubled design, albeit less troubled than the Panzer III. It quickly outgrew the chassis and running gear, especially after the KwK40 was shoe-horned into it. Weight issues limited armor and eventually led to dropping the powered traverse to save weight.

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I remain impressed with what the Aussies managed to do using the M3 drive train. The Sentinel project was overtaken by the capacity of US M4 production, but as indigenous design would have been more than adequate to counter Japanese armour in that theatre. Bovington have a nice example. --SJ